如何修复Drupal 8站点中损坏或缺失的区块？

Hey there, let's troubleshoot that broken/missing block issue in Drupal 8 together—this is a super common problem, and I’ve fixed it more times than I can count. Here’s a step-by-step breakdown of what to check:

The error message calls this out first, so let’s start here:

• Head to Extend (admin/modules) in your Drupal backend.
• Search for the module that provided this block. If you’re not sure which one it was, check the block’s machine name (you can find this in the block layout edit screen—it usually looks like [module_name]_block_[id]).
• If the module is disabled, turn it on, then clear your cache. Nine times out of ten, this fixes the issue right away.

If the module is enabled but the block is still broken, the content it’s supposed to display might be gone:

• Custom content blocks: Go to Structure > Custom blocks (admin/structure/block/block-content) and check if the block entry is still there. Accidental deletions happen more often than you think!
• View blocks: Navigate to Structure > Views (admin/structure/views) and confirm the view is active, and the specific display used by the block is enabled (not disabled or deleted).
• Menu blocks: Check Structure > Menus (admin/structure/menu) to make sure the menu tied to the block hasn’t been deleted or emptied.

Stale cache can sometimes leave behind broken references even after fixing the root issue:

• Go to Configuration > Performance (admin/config/development/performance) and click "Clear all caches".
• If you use Drush, run drush cache:rebuild in your terminal—it’s faster and works even if the backend is acting wonky.

If you recently installed or updated modules, that could be the culprit:

• Roll back any recent updates to the module that provides the block (if you have a backup) to see if that resolves the problem. Sometimes module updates break block definitions.
• Disable any newly installed modules one by one, clearing cache after each, to spot a conflict. A new module might be interfering with the block’s rendering.

If none of the above works, the logs will give you specific error details:

• Go to Reports > Recent log messages (admin/reports/dblog) and search for entries related to the block (use the block’s machine name or "broken block" as keywords). You might see errors like missing plugin classes or database table issues that point you to the exact problem.

If the block’s configuration is corrupted beyond repair, a recent database backup can save the day:

• Make sure to back up your current site first, then restore a backup from before the block started showing the error. This should bring back the block’s original configuration.

Start with the simplest steps first—enabling the module and clearing cache are the most frequent fixes. If you hit a wall, the logs will almost always give you the direction you need.

内容的提问来源于stack exchange，提问作者madan kumar